This invention relates generally to the field of air conditioning and engine enclosure ventilating systems for heavy machinery such as construction, earthmoving and other types of work machines and, more particularly, to a single fan arrangement and control system for simultaneously cooling the air conditioner condenser and ventilating the engine enclosure associated with a particular work machine.
Construction and excavation machines as well as a wide variety of other types of work machines typically include an operator compartment or cab for controlling the operation of the machine. Because of the varied environments in which these work machines are utilized, many of these operator cab compartments are equipped with air conditioning systems. An essential component of any air conditioning system is a refrigerant condenser core which is used to transfer heat from the refrigerant to some other medium. In this regard, condenser cores typically require forced air flow to be directed through the condenser in order to enhance heat transfer therefrom, and therefore enhance the performance of the air conditioning system. This forced air flow helps to further remove heat from the condenser core and improves the overall efficiency of the air conditioning system.
Because of space limitations, a separate fan for forcing air through the air conditioning condenser is normally not provided. Instead, condenser cores are often placed in a primary cooling fan air stream along with many other heat exchangers such as the engine""s radiator as well as hydraulic, transmission, and oil heat exchangers, all of which reduce the amount of heat transfer air flow through the air conditioning condenser core thereby reducing the effectiveness of the air conditioning system. This prior art arrangement also adds to the overall cooling system size, particularly the size and operational capability of the primary cooling fan, and such physical arrangement of the various cooling system components often times inhibits the operator""s visibility from the cab compartment.
It is desirable to improve the effectiveness of a work machine""s air conditioning system while at the same time minimizing the size of the equipment necessary to accomplish this task.
Another important and ever increasing need in work machines is engine enclosure ventilation in order to cool and maintain the temperature of the engine compartment below the critical temperature requirements of the various components installed therein. Additionally, noise regulations worldwide are requiring more noise-tight enclosures to attenuate engine noise. More noise-tight engine enclosures result in more air tight engine enclosures which, in turn, results in decreased natural air flow and decreased natural air circulation through the engine compartment to remove heat from the heat generating components. This results in decreased ventilation of the engine enclosure. In order to achieve a high noise-attenuated engine enclosure and still maintain the temperature requirements within such enclosure, a ventilation fan may be required to improve air circulation within the engine enclosure. Ventilation fans installed specifically to circumvent the engine enclosure ventilation problem, once again, add to the size of the overall cooling system.
It is therefore likewise desirable to improve the ventilation of the engine enclosure while at the same time minimizing the size of the cooling system necessary to accomplish this task.
Accordingly, the present invention is directed to overcoming one or more of the problems as set forth above.
In one aspect of the present invention, an apparatus for both increasing air flow through a heat transfer device and ventilating an engine compartment in a work machine is disclosed. The apparatus includes a fan positioned adjacent one end portion of the engine compartment, a heat exchanger device positioned adjacent to and upstream from the fan, and the fan creating air flow through the heat transfer device and through the engine compartment.
In another aspect of the present invention, a method for controlling the speed of a fan in a work machine, the work machine including a heat transfer device and an engine compartment, the fan being positioned between the heat transfer device and one end portion of the engine compartment is disclosed. The method comprising the steps of sensing a temperature in the engine compartment of the work machine, determining a fan speed based upon the temperature sensed in the engine compartment, sensing the operation of the heat transfer device, determining a fan speed based upon the operation of the heat transfer device, comparing the fan speed determined in the step of determining a fan speed based upon the temperature sensed in the engine compartment with the fan speed determined in the step of determining a fan speed based upon the operation of the heat transfer device, and setting the speed of the fan to the higher of the fan speeds determined in the step of determining a fan speed based upon the temperature sensed in the engine compartment and the step of determining a fan speed based upon the operation of the heat transfer device.